中国人肺癌p16基因失活的研究

目的：分析研究中国人肺癌中ｐ１６／ＣＤＫＮ２基因失活的情况，探讨该基因在肺癌发生、发展中的作用。方法：对２６例临床切除的原发性肺癌标本分别用甲基化特异性ＰＣＲ（ＭＳＰ）以及限制性内切酶－ＰＣＲ法检测了ｐ１６／ＣＤＫＮ２基因５’启动子区及第一外显子区ＣｐＧ岛甲基化的情况，选取与ｐ１６紧密连锁的Ｄ９Ｓ１７４８位点进行微卫星不稳定性分析，同时对其中１７例病例的肿瘤及癌旁组织标本用双色ＦＩＳＨ分析ｐ１６基因丢失情况，并用免疫组织化学法检测了ｐ１６蛋白表达。结果：用ＭＳＰ检测到５０％（１３／２６）的标本存…     

CDKN2基因CpG岛异常甲基化与原发性胃癌的关系研究

探讨原发性胃癌中抑癌基因ＣＤＫＮ２的灭活机制。方法ＰＣＲ┐甲基化检测法检测３６例胃癌和２２例正常胃粘膜组织中ＣＤＫＮ２基因外显子１的ＣｐＧ岛异常甲基化情况。结果有１３例（３６．１％）胃癌标本和１例（４．５％）正常胃组织中ＣＤＫＮ２基因５′端ＣｐＧ岛异常甲基化，两者之间有显著性差异（Ｐ＜０．０５）。结论ＣＤＫＮ２基因的５′端ＣｐＧ岛异常甲基化与胃癌的发生发展相关，是该基因在原发性胃癌中的主要灭活机制。     

子宫内膜癌中p16基因甲基化与表达的研究

目的 研究ｐ１６基因甲基化状态及其ｐ１６基因表达异常与子宫内膜癌发生发展的关系。方法 采用限制性内切酶酶切、ＰＣＲ及ＲＴ－ＰＣＲ检测子宫内膜检测ｐ１６基因５’ＣｐＧ岛甲基化状态及ｐ１６基因ｍＲＮＡ表达。结果 ８例正常子宫内膜无甲基化,且ｐ１６ ｍＲＮＡ表达正常。６例子宫内膜非典型增生中,有１例甲基化;３８例子宫内膜癌中,１３例甲基化,占３４．２％。６例子宫内膜单纯及复合增生中,有５例ｐ１６ ｍＲＮ     

非小细胞肺癌pl6/CDKN2基因失活的研究

目的：分析中国人非小细胞肺癌中ｐ１６／ＣＤＫＮ２基因失活的情况,探讨该基因在肺癌发生中的作用。方法：选取与ｐ１６基因紧密连锁的Ｄ９Ｓ１７４８位点,对１７例临床切除的原发性肺癌标本进行微卫星不稳定性分析,用甲基化特异性ＰＣＲ（ｍｅｔｈｙｌａｔｉｏｎ－ｓｐｅｃｉｆｉｃ ＰＣＲ, ＭＳＰ）检测 ｐｌ６基因启动子区 ＣｐＧ岛甲基化状况,用免疫组织化学法检测Ｐ１６蛋白表达情况。结果：微卫星不稳定性分析结果表明,在１３例Ｄ９Ｓ１７４８位点存在多态性的肿瘤ＤＮＡ中有 ９例（６９ ．２％）发生了杂合性缺失（ｌｏｓｓ ｏｆ ｈｅｔｅｒｏｚｙｇｏｓｉｔｙ, ＬＯＨ）。 ＭＳＰ的结果显示,有 ７０． ６％（１２／１７）的肿瘤组织存在ｐ１６启动子区的异常高甲基化。在本研究中,８２．４％（１４／１７）的肿瘤组织可以检测出一种或两种ｐ１６基因的异常改变。对此１７例肿瘤标本进行的免疫组织化学分析显示,有 １３例 Ｐ１６蛋白表达阴性,其中 ９２ ３％（１２／１３）存在一种或两种ｐ１６基因的异常改变。免疫组化结果与ｐ１６基因分子遗传学改变情况基本吻合。结论：作为一种抑癌基因,ｐ１６在多种肿瘤组织中都有异常改变。我们的研究表明,ｐ１６基因失表达是非小细胞肺癌     

结肠癌组织中p16／MTS1基因5′CpG岛甲基化研究

〔目的〕研究结肠癌组织中p１６基因５′端ＣpＧ岛异常甲基化现象。〔方法〕采用甲基化特异ＰＣＲ方法（ＭＳＰ）检测了２８例结肠癌和２０例癌旁正常组织标本。〔结果〕２８例结肠癌组织中有９例５′端ＣpＧ岛异常甲基化（３２％），而２０例正常组织中均阴性。〔结论〕p１６基因５′端ＣpＧ岛异常甲基化在人类结肠癌的发生中可能起一定作用。     

p16抑癌基因研究进展

ｐ１６基因（ＭＴＳ１，ＣＤＫ４Ｉ，ＣＤＫＮ２）是新近发现的抑癌基因。它以突变或缺失异常形式广泛存在于各种肿瘤细胞中。ｐ１６蛋白为细胞周期依赖激酶ＣＤＫ４的抑制物，参与正常细胞周期Ｇ→Ｓ期的调控，并与Ｒｂ、ｐ５３等抑癌基因有着密切联系。ｐ１６抑癌基因的...     

上皮源性恶性肿瘤患者p16抑癌基因甲基化研究

目的：了解中国人群上皮源性恶性肿瘤患者ｐ１６基因甲基化异常状况。方法：收集１３１例肺,食管、卵巢、子宫内膜,膀胱,喉,鼻咽癌患者肿瘤组织,甲基化敏感限制性内切酶ＳｍａＩ消化ＤＮＡ,ＰＣＲ扩增ｐ１６基因外显子,分析５‘ＣｐＧ岛异常甲基化。     

非小细胞肺癌p16基因突变的初步研究

为了解非小细胞肺癌（ＮＳＣＬＣ）ｐ１６基因突变的情况,本研究应用ＰＣＲ－ＳＳＣＰ银染技术检测了２４例ＮＳＣＬＣ肿瘤组织中ｐ１６基因外显子２的突变情况,现将结果报告如下。１　材料与方法２４例ＮＳＣＬＣ肿瘤组织及同一病例非肿瘤肺组织均为住院病例手术切除标本,并经病理证实。按常规方法提取ＤＮＡ。ＰＣＲ反应在ＰＥ９６００热循环仪中进行,扩增ｐ１６基因第２外显子,引物序列：　　ＰＳ１：５′－ＡＣＡＡＧＣＴＴＣＣＣＴＴＣＣＧＴＣＡＴＧＣ－３′ＰＳ２：５′－ＴＣＴＧＡＧＣＴＴＴＧＧＡＡＧＣＴＣＴＣＡＧ－３′循…     

人胎盘型谷胱甘肽S转移酶在胃癌组织中的表达与基因甲基化关系的研究

目的：研究胃癌组织中ＧＳＴ－π的表达与其基因甲基化状态的关系。方法：应用Ｓ－Ｐ法检测１１６例胃癌和５３例胃癌前病变的ＧＳＴ－π表达和限制性内切酶及ＰＣＲ、Ｓｏｕｔｈｅｒｎ印迹方法检测１４例胃癌及其相应正常胃粘膜ＧＳＴ－πＤＮＡ５′端调控区ＣＣＧＧ特定位点的甲基化水平。结果：ＧＳＴ－π阳性率,正常胃粘膜１０％（４／３９）,胃癌７７％（８９／１１６）,肠上皮化生７６％（１９／２５）,不典型增生８９％（２５／２８）。ＧＳＴ－π在胃癌及癌前病变中的表达较正常胃粘膜增高（Ｐ＜００１）。胃癌组织中ＧＳＴ－π基因较正常胃粘膜呈现高度去甲基化（Ｐ＜００１）,胃癌ＧＳＴ－π基因５′端调控区低甲基化与其ＧＳＴ－π表达增加呈相关性（Ｐ＜００５）。结论：ＧＳＴ－π在胃癌及癌前病变中的表达与胃癌的发生发展密切相关,ＧＳＴ－π可作为胃癌的肿瘤相关抗原;ＧＳＴ－π基因５′端调控区低甲基化可能是ＧＳＴ－π高表达的分子机理。     

胃癌患者p53基因甲基化的研究

作者应用限制性内切酶ＨｐａⅡ和ＭｓｐⅠ酶切胃癌组织及正常胃组织ＤＮＡ，经ＰＣＲ扩增ｐ５３基因第５外显子，琼脂糖凝胶电泳分析其电泳图谱，比较胃癌组织及正常胃组织ｐ５３基因第５外显子特定序列５′－ＣＣＧＧ－３′位点甲基化差异。结果显示：１５例胃癌组织中１２例ｐ５３基因第５外显子出现高甲基化状态，而１０例正常胃组织为低甲基化状态，结果提示，ｐ５３基因高甲基化状态与胃癌发生有关。     

Inactivation of the CDKN2/pl6 gene induced by methylation at 5′-CpG Island and its relation to lung cancer

Objectives: To investigate the methylation status of the CDKN2/pl6 gene 5′-CpG island, and study the relationship between the CDKN2/pl6 gene inactivation by methylation and lung cancer. Methods: Genomic DNA extracted from the specimens of lung cancer and normal lung tissue was digested with methylation-sensitive endonucleases, and Southern blotting was used to analyze the methylation status of the CDKN2/pl6 gene in 89 cases of lung cancer and 10 cases of normal lung tissue. Results: In 89 cases of lung cancer studied, the CDKN2/pl6 gene was shown to be methylated in 21 cases with the total methylation rate of 23.6% (21/89), in which there were 15 cases (16.9%) methylated atSmaI sites, 12 cases (13.5%) atSmaI sites and 6 cases at bothSmaI andSacII sites. The methylation of the CDKN2/pl6 gene occurred in 17 among 42 of pl6 protein negative cases of lung cancer with a rate of 40.5% (17/42), and in 3 among 47 of pl6 protein positive cases with a rate of 6.4% (3/47). The CDKN2/pl6 gene was not methylated in 10 cases of normal lung tissue. Conclusion: The aberrant methylation of the CDKN2/pl6 gene 5′-CpG island is probably an important mechanism of the gene inactivation, it may be involved in the genesis and progress of lung cancer. Foundation item: This work was supported by a grant from the National 9th Five-Year Plan Key Project (No. 96-906-01-18) and the National Natural Science Foundation of China (No. 39670714). Biography: SU Chang-qing (1964-), doctor of medicine, associate professor, Cancer Center of the Chinese People’s Liberation Army (PLA), Nanjing 81st Hospital, majors in molecular biology of cancer.     

Molecular pathology shows p16 methylation in nonadenomatous pituitaries from patients with Cushing's disease.

PURPOSE: The majority of cases of Cushing's disease are due to the presence of a corticotroph microadenoma. Less frequently no adenoma is found and histology shows either corticotroph hyperplasia, or apparently normal pituitary. In this study we have used molecular pathology to determine whether the tissue labeled histologically as "normal" is indeed abnormal. EXPERIMENTAL DESIGN: Tissue from 31 corticotroph adenomas and 16 nonadenomatous pituitaries were subject to methylation-sensitive PCR to determine the methylation status of the p16 gene CpG island. The proportion of methylated versus unmethylated CpG island was determined using combined bisulphite restriction analysis. Methylation status was correlated with immunohistochemical detection of p16. RESULTS: Seventeen of 31 adenomas (54.8%), 4 of 6 cases of corticotroph hyperplasia, and 7 of 10 apparently normal pituitaries showed p16 methylation. Ten of 14 (71%; P = 0.01) adenomas and 2 of 3 cases of corticotroph hyperplasia, which were methylated, failed to express p16 protein. However, only 2 of 7 apparently normal pituitaries that were methylated failed to express p16 protein. Quantitative analysis of methylation using combined bisulphite restriction analysis showed only unmethylated CpG islands in postmortem normal pituitaries; however, in adenomas 80-90% of the cells within a specimen were methylated. The reverse was true for corticotroph hyperplasia and apparently normal pituitaries where only 10-20% of the cells were methylated. Thus, the decreased proportion of cells that were methylated, particularly in those cases of apparently normal pituitary, is the most likely explanation for the lack of association between this change and loss of cognate protein in these cases. CONCLUSIONS: To our knowledge this is the first report that describes an intrinsic molecular change, namely methylation of the p16 gene CpG island, common to all three histological patterns associated with Cushing's disease. Thus, the use of molecular pathology reveals abnormalities undetected by routine pathological investigation. In cases of "apparently" normal pituitaries it is not possible to determine whether the change is associated with adenoma cells "scattered" throughout the gland, albeit few in number, or with the ancestor-clonal origin of these tumor cells.     

宫颈癌组织中FHIT基因5'端CpG岛甲基化及其与基因失活的关系

背景与目的:脆性组氨酸三联基因(fragile histidine triad gene,FHIT)作为抑癌基因与多种实体瘤的发生有关,并在多种肿瘤中因甲基化而失活。本研究拟探讨宫颈癌组织中FHIT基因5'端CpG岛甲基化状况及其与基因失活的关系。方法:采用甲基化特异性聚合酶链反应(methylation鄄specificPCR,MSP)和免疫组织化学法分别检测10例正常宫颈鳞状上皮、40例宫颈癌组织中FHIT基因5'端CpG岛的甲基化发生状况和FHIT蛋白表达情况。结果:(1)正常宫颈鳞状上皮组织中未发现存在FHIT基因甲基化状态,而宫颈癌组织中FHIT基因5'端CpG岛的甲基化率为40.0%(16/40);(2)临床Ⅱ期宫颈癌病例中FHIT基因甲基化的发生率为56.5%(13/23),明显高于Ⅰ期的14.3%(2/14)(P<0.05);(3)宫颈癌组织中存在FHIT蛋白表达降低或缺失,阳性率仅为30.0%(12/40),显著低于正常宫颈组织的100.0%(10/10)(P<0.05)。结论:FHIT基因5'端CpG岛甲基化是宫颈癌中该基因失活的机制之一,可能与宫颈癌的发生发展有关。     

DNA methylation in the promoter region of the p16 (CDKN2/MTS-1/INK4A) gene in human breast tumours

The p16 (CDKN2/MTS-1/INK4A) gene is one of several tumour-suppressor genes that have been shown to be inactivated by DNA methylation in various human cancers including breast tumours. We have used bisulphite genomic sequencing to examine the detailed sequence specificity of DNA methylation in the CpG island promoter/exon 1 region in the p16 gene in DNA from a series of human breast cancer specimens and normal human breast tissue (from reductive mammaplasty). The p16 region examined was unmethylated in the four normal human breast specimens and in four out of nine breast tumours. In the other five independent breast tumour specimens, a uniform pattern of DNA methylation was observed. Of the nine major sites of DNA methylation in the amplified region from these tumour DNAs, four were in non-CG sequences. This unusual concentration of non-CG methylation sites was not a general phenomenon present throughout the genome of these tumour cells because the methylated CpG island regions of interspersed L1 repeats had a pattern of (almost exclusively) CG methylation similar to that found in normal breast tissue DNA and in DNA from tumours with unmethylated p16 genes. These data suggest that DNA methylation of the p16 gene in some breast tumours could be the result of an active process that generates a discrete methylation pattern and, hence, could ultimately be amenable to theraputic manipulation. © 1999 Cancer Research Campaign